Nickolai V. Shadrin

Current Invasions of Asian Cyclopid Species (Copepoda: Cyclopidae) in Crimea, with Taxonomical and Zoogeographical Remarks on the Hypersaline and Freshwater Fauna

Abstract. The Crimean Peninsula holds a large number of hypersaline water bodies. Our studies focused on these poorly investigated habitats, and included few brackish and freshwater ponds. Seventeen species were identified, of which only 4(5) were collected from hypersaline waters sometimes with extremely high salinities (Acanthocyclops sp. copepodid, 210 ppt; Eucyclops sp. copepodid, 150 ppt; Diacyclops bisetosus and Cyclops furcifer, 140–150 ppt). We also report on the occurrence of three alien thermophilic species (Eucyclops roseus Ishida, 1997, Mesocyclops isabellae Dussart et Fernando, 1988, and Mesocyclops pehpeiensis Hu, 1943) from the brackish and fresh waters of Crimea. Morphological descriptions, illustrations of the diagnostic characters and comments on relevant taxonomic issues are supplemented with discussion of the putative ways of dispersal of the alien copepods to Crimea. We provisionally reinstate Eucyclops roseus, regarded by others as a subspecies of E. agiloides (G. O. Sars, 1909), and retain the name Acanthocyclops trajani Mirabdullayev et Defaye, 2002 which was recently synonymized with A. americanus (Marsh, 1893) here considered a nomen dubium. Species accumulation curves based on our and literature data showed that significantly larger sampling efforts could yield a total of 6–8 species in the hypersaline waters and 47–50 species in all types of continental waters of Crimea.

Does salinity change determine zooplankton variability in the saline Qarun Lake (Egypt)

Zooplankton and 14 abiotic variables were studied during August 2011 at 10 stations in Lake Qarun, Egypt. Stations with the lowest salinity and highest nutrient concentrations and turbidity were close to the discharge of waters from the El-Bats and El-Wadi drainage systems. A total of 15 holozooplankton species were identified. The salinity in Lake Qarun increased and fluctuated since 1901: 12 g/L in 1901; 8.5 g/L in 1905; 12.0 g/L in 1922; 30.0 g/L in 1985; 38.7 g/L in 1994; 35.3 g/L in 2006, and 33.4 g/L in 2011. The mean concentration of nutrients (nitrate, nitrite and orthophosphate) gradually increased from 35, 0.16 and 0.38 µg/L, respectively, in 1953–1955 to 113, 16.4, and 30.26 µg/L in 2011. From 1999–2003 some decrease of species diversity occurred. Average total zooplankton density was 30 000 ind./m3 in 1974–1977; 356 125 ind./m3 in 1989; 534 000 ind./m3 in 1994–1995; from 965 000 to 1 452 000 ind./m3 in 2006, and 595 000 ind./m3 in 2011. A range of long-term summer salinity variability during the last decades was very similar to a range of salinity spatial variability in summer 2011. There is no significant correlation between zooplankton abundance and salinity in spatial and long-term changes. We conclude that salinity fluctuations since at least 1955 did not directly drive the changes of composition and abundance of zooplankton in the lake. A marine community had formed in the lake, and it continues to change. One of the main drivers of this change is a regular introduction and a pressure of alien species on the existent community. Eutrophication also plays an important role. The introduction of Mnemiopsis leidyi, first reported in 2014, may lead to a start of a new stage of the biotic changes in Lake Qarun, when eutrophication and the population dynamics of this ctenophore will be main drivers of the ecosystem change.

Dormant stages of crustaceans as a mechanism of propagation in the extreme and unpredictable environment in the Crimean hypersaline lakes

A pool of dormant stages of planktonic organisms in saline lakes is a substantial component in the plankton communities; we need to take it into account to understand plankton dynamics. Hypersaline water bodies in Crimea, the largest peninsula in the Black Sea, constitute a very characteristic and peculiar habitat type in the region. We examined the presence of crustacean resting stages in sediments of dried up sites of the Crimean hypersaline lakes. Sediment samples were taken in 9 different lakes. Experiments performed on the hatching of these resting stages showed the presence of Moina salina (Cladocera), parthenogenetic Artemia and Artemia urmiana (Anostraca), Eucypris mareotica (inflata) (Ostracoda), and Cletocamptus retrogressus (Harpacticoida). Comparing the experimental results obtained with clean dried brine shrimp cysts and those kept in sediment samples, it was noted that clean cysts hatched much faster than those from sediments did. Some components in bottom sediments slow down and desynchronize hatching from resting eggs in different groups of crustaceans. The sediments of different lakes inhibited the nauplii output from Artemia and ostracod resting eggs to different degrees. More data are needed before we can discuss the reasons of this inhibition. The nonsynchronous output of active stages from the bottom resting ones may be an adaptation that allows crustacean species to exist in extreme and unpredictably changing environments, avoiding the risk that all may emerge at once under unsuitable conditions.

Resting Stages of Crustaceans in the Crimean Hypersaline Lakes (Ukraine) and Their Ecological Role

1 Introduction A presence of resting stages in various aquatic organisms is a long-known phenomenon as a mechanism of species adaptation to exist in unstable aquatic habitats,surviving adverse conditions in thesleepingstate(Radzikowski,2013).Bank of resting stages of planktonic organisms is an important component of the plankton community,without which we cannot understand community dynamics(Brendonck and De Meester,2003).

Intentional introduction of Artemia sinica (Anostraca) in the high-altitude Tibetan lake Dangxiong Co: the new population and consequences for the environment and for humans

The imbalance between supply and demand of Artemia cysts in China and around the world is increasing now. Salt lakes in Tibet may contribute to the solution of the problem. In Northern Tibet there are 26 saline lakes whose salinity and temperature may support Artemia survival at an altitude of 4 000–5 100 m. We found Artemia in 15 of these lakes. The saline lakes with Artemia populations mainly belong to the shallow basin lakes, and the majority of these lakes are small in area. The total area of lakes without Artemia is more than 1 000 km2. Lake Dangxiong Co (Co means lake in Tibet) was chosen for the intentional introduction of Artemia sinica. In 2004, 850 g of A. sinica cysts, originating from Qinghai, were introduced in the lake. Surveys in 2006–2014 showed that the average abundance of Artemia adults in the lake gradually increased from 20 ind./m3 in 2006 to 1950 ind./m3 in 2013. We assume that two subpopulations of A. sinica, separated by depth, may exist in the lake. The new Artemia population caused an increase in the number of species of phytoplankton and heterotrophic protozoa with a decrease of their total abundance. Water transparency also increased. Dominance in phytoplankton passed from cyanobacteria to diatoms. Changes occurred not only in the lake ecosystem; the number of water birds using the lakes also dramatically increased. Preliminary calculations showed that is it possible to harvest at least about 150 t cysts per year from the lake as well as 3.2 thousand tons of frozen or 350 t of dried biomass of adult Artemia.

Transformation of Gulf Sivash (the Sea of Azov) in Conditions of Growing Salinity: Changes of Meiobenthos and Other Ecosystem Components (2013-2015)

Nickolai V. Shadrinа,*, Nelli G. Sergeevaа, Aleksandr A. Latushkinb, Еlena А. Kolesnikovaа, Laura M. Kipriyanovac, Elena V. Anufriievaа and Anna A. Chepyzhenkob aA.O. Kovalevsky Institute of Marine Biological Research RAS 2 Nakhimov, Sevastopol, 299011, Russia bMarine Hydrophysical Institute RAS 2 Kapitanskaya Str., Sevastopol, 299011, Russia cInstitute for Water and Environmental Problems SB RAS 2 Morskoy, Novosibirsk, 630090, Russia

Factors determining the average body size of geographically separated Arctodiaptomus salinus (Daday, 1885) populations

Arctodiaptomus salinus inhabits water bodies across Eurasia and North Africa. Based on our own data and that from the literature, we analyzed the influences of several factors on the intra- and inter-population variability of this species. A strong negative linear correlation between temperature and average body size in the Crimean and African populations was found, in which the parameters might be influenced by salinity. Meanwhile, a significant negative correlation between female body size and the altitude of habitats was found by comparing body size in populations from different regions. Individuals from environments with highly varying abiotic parameters, e.g. temporary reservoirs, had a larger body size than individuals from permanent water bodies. The changes in average body mass in populations were at 11.4 times, whereas, those in individual metabolic activities were at 6.2 times. Moreover, two size groups of A. salinus in the Crimean and the Siberian lakes were observed. The ratio of female length to male length fluctuated between 1.02 and 1.30. The average size of A. salinus in populations and its variations were determined by both genetic and environmental factors. However, the parities of these factors were unequal in either spatial or temporal scales.

Copepoda in the shallow hypersaline Bardawil coastal lake (Egypt): Are there long-term changes in composition and abundance?

Abstract Coastal Lake Bardawil (Egypt) is one of the largest hypersaline lakes in the world. In 2009–2010, the authors studied composition, distribution and seasonal dynamics of copepods at 12 sites. A total of 10 species of copepods were recorded in zooplankton during the study period, including 5 Calanoida, 2 Cyclopoida and 3 Harpacticoida. Oithona nana was the most common and most abundant species. All copepods in the lake can be divided into three groups: 1) planktic species that form stable populations, 2) species of Mediterranean plankton incidentally entering the lake from the adjacent sea area, 3) benthic Cyclopoida and Harpacticoida that can be abundant in plankton. Two species – Acartia tonsa and A. danae were recorded here for the first time. The total abundance of copepods in the lake was significantly higher (90 times on average) compared to that observed in 2008–2009 in the waters of the Egyptian Mediterranean Sea. Since 1967, the complex of common and dominant copepod species in the lake has changed significantly. The total average annual copepod abundance varied: in 2002 – it was about 4000 ind. m−3, in 2004 – 152 000 ind. m−3, in 2005 – about 25 300 ind. m−3, and in 2009–2010 – about 56 000 ind. m−3.

Mesochra rostrata Gurney, 1927 (Copepoda, Harpacticoida) in Sivash Bay (Sea of Azov): Is it a new alien species or a relict of Tethys?

Harpacticoid Mesochra rostrata Gurney, 1927 was found in Sivash Bay (Sea of Azov) for the first time in 2013. In 2015, it became the most common and abundant species of Harpacticoida in the bay. The morphological characteristics of males and females of M. rostrata found in the Sivash accord with the species description given in earlier publications. The bay population comprised adult males and females, naupliar and copepodite stages. Adult male size varied from 0.30 to 0.40 mm, and adult female size varied from 0.38 to 0.45 mm. Since 2014, a substantial increase in salinity has been observed in Sivash Bay. In August 2015, seven species of Harpacticoida were registered in the bay in total; M. rostrata dominated and was abundant in benthos (up to 56000 ind./m2), in the floating mats of filamentous green algae (up to 336 400 ind./m2), and in plankton (up to 580 ind./m3) at water salinity of 60–75 g/L. Earlier, this species was registered in the Sinai Peninsula at the water salinity not exceeding 45 g/L. M. rostrata can be considered a new invader in the Azov-Black Sea Region; the resting stage of this crustacean was brought here by wind or birds. However, it can be assumed also that the species is an aboriginal one for the Azov-Black Sea Region from times of the Tethys Ocean. In the Black and Mediterranean seas, there are some relicts of Tethys. In normal conditions, this species is rare and, possibly, can succeed only in destabilized biotopes, such as Sivash Bay nowadays during the period of a sharp increase in the water salinity.

Size polymorphism and fluctuating asymmetry of Artemia (Branchiopoda: Anostraca) populations from the Crimea

Received 11.11.2016, received in revised form 23.12.2016, accepted 17.01.2017 Fluctuating asymmetry (FA) of animals as a measure of ontogenetic stability is widely used in environmental bioindication. Environmental stress leads to increased levels of FA within populations. Artemia (Anostraca) is among the most primitive and ancient groups of crustaceans, inhabiting hypersaline waters worldwide. Despite of this there are only few studies on FA in Artemia populations, showing opposite results. To assess FA we used length of the first antenna and number of furcal setae on left and right sides. In 2004–2013 the samples were collected from 10 hypersaline lakes in Crimea. Two size groups presented in the studied lakes; diploids constitute a small size group, and polyploids – a larger one. Average length in both groups significantly correlated with salinity. No one directed influence of salinity on FA was found. Manifestation of FA was different in small and large size groups. Changes in salinity can explain not more than 40–55 % of FA variability for studied traits. Parthenogenetic populations of Artemia in Crimean lakes have differences in FA manifestation, which may be explained by differences in water salinity, genetic architecture, and selective pressure against individuals with highest FA. We cannot explain the observed FA differences in studied Artemia populations.